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On my first environmental economics quiz I asked my students to come up with an example of an environmental alarmist using big numbers to make a point. Typically those numbers are used with the express intention of scaring the daylights out of readers, perhaps to argue from intimidation, and very rarely (never?) are they juxtaposed with something that will help us assess the marginal importance of such numbers.

I’d love to post my top 5 favorites, but again cannot due to our students’ remarkable ability to google for stuff. As a somewhat reasonable illustration, imagine if I told you something about how my weight has increased since I hurt my calves two weeks ago (I hate taking “off” but I think I have to). I have gained 1.4 trillion nanograms in just two weeks. 1.4 trillion! Wow, scary! I’ve put on the pounds.

Of course, before the sedentary prison sentence I happened to weigh about 80 trillion nanograms and I’ve gained about three pounds. I could of course do the opposite and use small numbers to obscure what is going on too. I’ve only gained 0.0015 tons in two weeks. Or even better, I’ve only gained 0.0000000015 megatons in the previous two weeks. No big deal, right! There’s nothing “right or wrong” about the choice of units or even making illustrations of the awesome scale of something – but they are virtually meaningless without some context. That “context” in economics is what we mean by the “margin.”

4 Responses to “The Big Numbers Boogeyman”

  1. “The Koch Industries Carbon Footprint Is About 300 Million Tons. With the assumption that Koch has a carbon intensity on the order of oil majors such as Chevron and ExxonMobil, each billion dollars of revenue corresponds to 2 to 4 million tons of carbon dioxide-equivalent greenhouse gases. Therefore, each year, Koch Industries is likely responsible for about 300 million tons of carbon dioxide pollution every year.” — Think Progress here

    But the Earth’s atmosphere weighs 5.3 E18 kg. (Physics @Suite101 here.) That is about 5.3 E15 metric tonnes. The atmosphere being .0394% CO2 (Wikipedia here)
    2,090,585,000,000 tons of CO2 total (2.1 E12). So, their 300 million (3.0 E8) short (avoirdupoids) tons is about 1 ten-thousandth of that total.

    Also, it is highly likely that if polled, the trees, shrubs, and grasses would all approve, though they would be disposed to locking up the carbon in their trunks, limbs, stalks, stems, while releasing O2 for us to breath in (breathing out more CO2, presumably, a biproduct of our Krebs Cycle).

  2. Harry says:

    Good work, Chuck.

    Let’s hear it for the Plant Kingdom! Without it, who knows what the concentration of CO2 would be at IPCC headquarters?

  3. Harry says:

    Geez, that wasn’t Chuck, it was MM. Sorry, MM!

    At any rate, it is important to put things in context. I get a chuckle every day with news people reporting a hundred point change in the DJIA, and then adding a reason for it. A couple of days ago a rise was attributed to the Europeans having solved for now the problem of Spain’s insolvent banks. My comment is, don’t believe everything you read in books.

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